It's been my experience that most scars never go away, but based on the size and location may be less prominent over time. If the scars are the result of recent injuries, they tend to look better after several sheds, however they don't go away entirely. Many injuries severe enough to cause some scarring also affect the growth of scales so after subsequent sheds, scales and scars may take on a puckered or stretched appearance. I'd be more concerned about what caused the injury, as many injuries [eg. burns, rat bites] are indicative of poor care and poor husbandry.
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Matt Campbell
Animal Keeper, Small Mammal/Reptile House
Lincoln Park Zoo Chicago, Illinois
Assistant Curator
Wildlife Discovery Center at Elawa Farm
Lake Forest, Illinois